Airway microbiology in tracheostomized children

Abstract

BACKGROUND: Potentially pathogenic microorganisms are frequently isolated from tracheostom-ized children, although evidence for empirical therapy of respiratory exacerbation is limited. We aimed to describe upper airway microbiology as found on endotracheal aspirate (ETA) in tracheos-tomized children and to correlate it with lower airway microbiology through bronchoalveolar lavage fluid. METHODS: We retrospectively reviewed records and airway microbiology of all tracheos-tomized children under the follow-up care of Queensland Children’s Hospital. Subanalysis was based on ventilatory and multidrug-resistant organism status. Sensitivity and specificity of ETA for pre-dicting Pseudomonas aeruginosa and Staphylococcus aureus lower airway isolation were calculated using concomitant bronchoalveolar lavage fluid culture as the accepted standard. RESULTS: From 43 children (18 female, median [interquartile range (IQR)] age 68 (41–115) months, 14 ventilated), 15 different potentially pathogenic microorganisms were isolated (mean ± SD: 3.30 ± 2.23), with S. aureus (n = 33, 77%) and P. aeruginosa (n = 29, 67%) predominating. Significantly more types of potentially pathogenic microorganisms were isolated from ventilated children (median 4.00 [IQR 3.25–5.75]) than from nonventilated children (median 2.00 [IQR 1.00–4.00] (P = .007), with 93% of ventilated children isolating S. aureus and 86% P. aeruginosa. Multidrug-resistant organisms were present in 12 (28%) children, of whom 8 were ventilated. Methicillin-resistant S. aureus (MRSA) was isolated in 9 (21%) children, of whom 6 were ventilated. For P. aeruginosa and S. aureus isola-tion, ETA had high sensitivity (95% and 100%, respectively) but low specificity (64.7% and 33.3%, respectively) when compared with bronchoalveolar lavage fluid. CONCLUSIONS: In children with tracheostomy, the predominant respiratory bacterial pathogens were S. aureus and P. aeruginosa, with MRSA being isolated less frequently than previously described. Multidrug-resistant organisms are isolated more frequently from ventilated children. ETA microbiology is a good screening modal-ity, with negative ETA potentially ruling out lower airway S. aureus and P. aeruginosa. Adequately powered prospective studies with quantitative cultures could enhance understanding and guide therapy.